The description herein relates to information handling systems and electrostatic discharge testing related to such systems.
As the value and use of information continue to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system (“IHS”) generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
An electrostatic discharge (ESD) is the transfer of an electric charge from one object to another, through contact between the two objects or through spark (charge flow through an ionized conductive channel formed in a gas under high electric fields). The initial potential difference between the two objects may be hundreds or thousands of volts, which is rapidly reduced as charge is transferred between the objects.
Various information handling systems electronic components, such as integrated circuits, are sensitive to electrostatic discharge. An ESD pulse that enters an integrated circuit may cause temporary or permanent circuit malfunction, e.g., by breaking through thin insulating layers, triggering latch-up in CMOS devices, and short-circuiting reverse-biased PN junctions. The ESD pulse may be a primary discharge (e.g., from a human to a circuit board) or a secondary discharge, between two system components, that occurs after a primary discharge to one of the two components. Consequently, design at the circuit, device, component, and system level can benefit from efforts to avoid, mitigate, and/or harmlessly dissipate electrostatic discharges that may occur during assembly or operation of an information handling system. As circuits, circuit boards, and systems scale to smaller sizes, ESD management generally becomes more critical.
Device test conditions and ESD waveforms have been specified for several modeled ESD events. Common modeled ESD events include the human body model (HBM), the human-holding-a-metallic-object system-level model (HMM), the machine model (MM), and the charged device model (CDM). ESD pulse generators capable of generating pulses according to such models exist, and are used to test components and/or entire information handling systems. Device sensitivity is generally different for each type of modeled ESD event.